Apple has refreshed its iMac line with more firepower that could drive some faithfuls to upgrade early. The Mac-maker is delivering new machines equipped with fourth-generation Intel quad-core processors, also known as Haswell chips.

The latest iMacs also don new graphics, next-generation Wi-Fi and faster PCIe flash storage options. The updated computers deliver plenty of new technology bells and whistles with the same thin design and display all-in-one Apple desktop fans lay down thousands of dollars to buy.

"iMac continues to be the example that proves how beautiful, fast and fun a desktop computer can be," said Philip Schiller, Apple's senior vice president of Worldwide Marketing. "Inside its ultra-thin aluminum enclosure, the new iMac has the latest Intel processors, faster graphics, next generation 802.11ac Wi-Fi and faster PCIe flash storage."

Major Mac Upgrades

The entry-level 21.5-inch iMac features a 2.7 GHz quad-core Intel Core i5 processor and new Iris Pro graphics for better integrated graphics performance. The high-end 21.5-inch model and both 27-inch models feature quad-core Intel Core i5 processors up to 3.4 GHz and Nvidia GeForce 700 series graphics with twice the video memory and up to 40 percent faster performance than the previous generation. Customers looking for even more performance can upgrade to quad-core Intel Core i7 processors up to 3.5 GHz and Nvidia GeForce GTX 780M series graphics with up to 4GB of video memory.

iMac now also supports next generation 802.11ac Wi-Fi. When connected to an 802.11ac base station, Apple said the machine delivers wireless performance that is up to three times faster than the previous generation.

The updated iMac now features support for PCIe-based flash storage that makes Fusion Drive and all-flash storage options up to 50 percent faster than the previous generation. The Fusion Drive option combines the large storage capacity of a hard drive with the high performance of flash to deliver shorter boot times and faster access to apps and files. Customers can configure their iMacs with 1TB or 3TB Fusion Drives, and all-flash storage options are now available in configurations up to 1TB.

The Baseline for New Macs

We asked Ross Rubin, principal analyst at Reticle Research, for his take on the upgrades. He told us the changes are consistent with some of the ones we've seen Apple implement on the MacBook Air.

"It's clear that they will be part of the baseline for new Macs," Rubin said. "802.11ac is also supported by Apple's new AirPort router so it makes sense to support the standard in its computers."

The iMac comes standard with 8GB of memory and a 1TB hard drive, and customers can choose to configure their iMacs with up to 32GB of memory and up to 3TB hard drives. The machine also comes with two Thunderbolt and four USB 3.0 ports for connecting to external storage and other high performance peripherals. The new iMacs are available now.

The 21.5-inch iMac is available with a 2.7 GHz quad-core Intel Core i5 with Turbo Boost speeds up to 3.2 GHz and Intel Iris Pro for $1,299. The 2.9 GHz quad-core Intel Core i5 with Turbo Boost speeds up to 3.6 GHz and Nvidia GeForce GT 750M sells for $1,499.

The 27-inch iMac is available with a 3.2 GHz quad-core Intel Core i5 with Turbo Boost speeds up to 3.6 GHz and Nvidia GeForce GTX 755M for $1,799. With a 3.4 GHz quad-core Intel Core i5 with Turbo Boost speeds up to 3.8 GHz and Nvidia GeForce GTX 775M sells for $1,999.